Dilution zone density detector



Dec. 7, 1965 H. T. PETERsoN 3,221,538

DILUTION ZONE DENSITY DETECTOR Filed Feb. 15, 196s INVENTOR. w naaf T T. PETERso/v h BY 'w QM Q` ,QM

Arran/5y l United States Patent O 3,221,538 DTLUTION ZONE DENSTTY DETECTOR Herbert T. Peterson, Longview, Wash., assigner to Weyerhaeuser Company, Tacoma, Wash., a corporation of Washington Filed Feb. 15, 1963, Ser. No. 258,722 6 Claims. (Cl. 73-32) This invention relates to a detector for use with a bleaching or neutralizing tower. More specifically, this invention relates to an apparatus for detecting the density of stock flowing through a bleaching or neutralizing tower.

In the art of bleaching or neutralizing chemicals added to materials, it is the practice to dump the stock, having the chemicals or neutralizer already added thereto, into the top of a large elongated tower at a consistency of about 15% and pumped out the bottom ot the tower at a stock consistency of about 3%. This requires that a large amount of dilution water be added to the stock. The dilution water is usually injected into the tower at its mid-portion with the height of the water in the tower maintained at a predetermined level.

With the dilution water at a predetermined level in the tower, a slurry will be produced having a predetermined density when the stock and dilution water are mixed together.

Therefore, it is important that the height of the dilu tion water in the tower or the height of the dilution zone in the tower be known and controlled because the reaction rate of the chemicals in the tower will be substantially reduced and in some cases will stop if too much dilution water is added to the tower. Moreover, if too little water is added to the tower, the resulting slurry will be too thick and will clog up the pump that removes the slurry from the tower in addition to other apparatus used in the production procedure.

I have developed a dilution zone detector which indicates the density of the slurry within the dilution zone in the tower. The dilution zone detector generally corn prises a feeler arm having an end portion extending into the tower and an end portion extending outside the tower with a counterweight attached thereto.

The feeler arm is designed and arranged to operate on a balance principle. As the stock is extracted from the bottom of the tower, the downward motion of the stock creates a force that acts on the portion of the feeler arm within the tower and will compel the inner arm portion to align itself with this motion or force. The force acting upon the inner portion of the arm will be in direct proportion to the weight or density of the stock. As the inner arm portion aligns itself with this force, the outer arm portion having the counterweight will be deflected. This deflection or angle of the counterweight can be calibrated to indicate the weight or density of the stock ilowing through the tower.

An object of this invention is to provide an apparatus that accurately indicates the density of the stock flowing in a reaction tower.

Another object of this invention is to provide a device that will react to the force of stock flowing through the tower to indicate the density of the stock therein.

These and other objects and advantages will become manifestly clear to those skilled in the art when taken in conjunction with the detailed description and drawings, wherein:

FIGURE 1 is a schematic cross-sectional view of a reaction tower illustrating the manner of mounting the dilution zone detector.

FIGURE 2 is a quarter sectional view of the dilution zone detector.

Referring to the drawings, a reaction tower 7 is shown in FIGURE l embodying the present invention. The reaction tower l is closed at its lower end with a plate member 31 rigidly attached thereto as by threads 32. In the center of the plate 31, a pipe 33 is threaded into the plate at 34 and has a pump 35 connected thereto so that the stock poured into the top may be pumped out to other apparatus in the production line.

Rigidly attached to the midportion of the reaction tower 7 is a header structure 24 which communicates with a dilution water source by pipe 26 connected thereto by threads 23. Holes or openings 25 communicate the interior of the header 24 with the interior of the reaction tower 7.

Mounted below the header structure 2d on support brackets, not shown, is an agitator means 36 which comprises a motor 37 having a shaft 38 extending therefrom and through the wall of the reaction tower 7. The shaft 38 of the agitator means 36 is connected to a propeller 39 which functions to agitate the stock within the tower 7.

Mounted above the header member 24 but below the height at which the dilution zone is to be maintained in the tower 7, is the dilution zone detector generally indicated at 1 of the present invention.

The dilution zone detector 1 generally comprises a feeler arm indicated at 2 with the end portions 4 and 6 bent at right angles with respect to mid-portion 5. The inner portion d of the feeler arm 2 is bent at right angles with respect to the mid-portion 5 as indicated at 3. The outer portion 6 is bent at right angles with respect to the mid-portion 5 as indicated at 6 but in a plane transverse to the plane defined by the inner portion 4 and midportion 5. In other words, the axis of the inner portion 4 is at right angles to the axis of the outer portion 6. As shown, a counterweight 23 is mounted on the end of the end portion 6 of the feeler arm 2.

The mid-portion 5 of the feeler arm 2 extends through the wall of the tower 7 and is attached thereto by a body member 11. The body member 11 extends into a bore 8 through the wall of the tower 7 and is rigidly attached thereto by threads 10. The body member 11 is provided with a bore 13 which receives the feeler arm portion 5. The outer portion of the bore 13 is enlarged to form a counterbore 14 which receives packing members 15 which are compressed by a packing gland 1S to form a fluidtight seal between the body member 11 and feeler arm portion 5. The outer portion of the body member 11 is provided with a flange portion 16 having threaded openings 17 for receiving a bolt 19 extending through a flange 2t) integrally connected to member 13 and extending through the holes 21. In this manner, the packing gland 1S may be compressed or extended into the counterbore 1d by tightening the bolts 19.

On the outside of the tower 7 but on the midportion 5 of the feeler arm 2 is mounted a pulley member 22 having a cable 29 extending therearound connected to another pulley, not shown, on a meter box 30 mounted on the outside of the reaction tower 7, for a purpose to be hereinafter described.

In operation, it will be assumed that there is no flow of stock through the reaction tower 7 and there is no dilution water therein. In this stage, the inner portion 4- of the feeler arm 2 will assume a horizontal position or a position that is transverse to the direction of ilow through the tower 7. The outer portion 6 having the counterweight 23 thereon will assume a vertical position with the axis thereof parallel to the axis of the reaction tower 7.

When it is desired to place the reaction tower 7 in operation, the operator turns the valve 27 on and allows dilution water to ll the tank up to a predetermined level,

above the dilution zone detector 1. A 15 consistency of pulp is then dumped into the top of the tower with the chemicals already added to the pulp. Enough time is now allowed to lapse for the chemicals to completely react and bleach the pulp. The pump 35 is now turned on and a 3% consistency of stock is now pumped out of the tower at a continuously constant rate. At the same time the dilution water inlet is opened by the valve 27 and allowed to continuously inject into the tower 7. Moreover, the 15% consistency pulp is dumped into the top of the tower 7. Also, the agitating means 36 is turned on and the propeller 39 continuously agitates the stock within the tower.

As the stock within-the tower 7 llows from the top to the bottom at a constant velocity, a force is created which acts on the end portion 4 of the feeler arm 2 and the arm portion 4 will tend to align itself with this force. In tending to align itself with this force, the portion 5 will be rotated in the body member 11 and will displace or deflect the end portion 6 on the outside of the tower at an angle from the vertical. Since the force acting on the inner end portion 4 is directly related to the weight or density of the stock within the tower, the angle of deflection of the end portion 6 from the vertical will be directly related to the weight or density of the stock within the tower. This angle of deection of the outer portion 6 can be calibrated to give an indication of the exact density of the stock within the tower.

As the mid-portion S rotates through the body 11, the pulley member 22 will be rotated therewith. By rotating the pulley 22, the cable 29 connected therearound will also be rotated.v Rotation of the cable 29 will rotate the pulley, not shown, on the meter box 30 and the position of the outer portion 6 or the angle of deflection of the portion 6 can be placed on a graph for observation.

Since the density of the stock Within the reaction tower 7 is related to the height of the dilution water within the tower, the operator need only to observe the angle of deflection of the outer portion 6 having counterweight 23 thereon or observe the graph on the meter box 30 to determine whether enough dilution water is within the reaction tower 7. If it is indicated that not enough dilution water is within the tower, the valve 27 is opened and a little more water is allowed to flow into the reaction tower through the header 24 and hole or openings 25. Conversely, if too much water is within the reaction tower 7, the operator need only close the valve 27.

In this manner, the operator has an exact control over the height of the dilution water within the reaction tower 7 to have a uniform reaction in the continuous operation.

While specific details of a preferred embodiment have been set forth above, it will be apparent that many changes and modifications may be made therein without departing from the spirit of the invention. It will therefore be understood that what has been described herein is intended to be illustrative only, and is not intended to limit the scope of the invention.

What is claimed is:

1. In combination: a continuous steady ow reaction tower having a source of dilution fluid connected thereto by a header means communicating with openings through said tower and a dilution zone detector, said dilution zone detector comprising: cylindrical arm means extending CTI 4ithrough the wall of said reaction tower, the inner portion of said cylindrical arm means being exposed to the force created by the flow of materials through said reaction tower, the outer portion of :said cylindrical arm means carrying a counterweight, and means mounting said cylindrical arm means in the wall of said reaction tower so that the inner portion of said cylindrical arm means can align itself with said force and deliect saidouter portion and counterweight, said mounting means comprising a body means having a bore therethrough threadedly connected to said reaction tower, and packing means carried by said body and adapted to form a seal around said cylindrical arm means extending through said bore, whereby the angle of deection of said counterweight can be calibrated to indicate the density of said materials flowing in said reaction tower.

2. The combination of claim 1 together with an agitator means connected to said reaction tower.

3. The combination of claim ltogether with a pulley means connected to the outer portion of said arm means having a belt connecting said pulley and a meter box for graphing the angle of deflection of said counterweight.

4. The combination of claim 1 wherein said body is provided with a counterbore for receiving said packing means and a packing gland attached to said body means and engaging said packing means.

5. A dilution zone detector for use with a continuous steady iiow reaction tower, comprising: an elongated cylindrical arm means adapted to be extended through the wall of said reaction tower, one end portion of said cylindrical arm means adapted to be extended into said reaction tower, another end portion of said cylindrical arm means adapted to be extended outside the reaction tower and carrying a counterweight, and means carried by said arm means adapted to mount said arm means through the wall of said reaction tower comprising a body having a bore and a counterbore for receiving said cylindrical arm means, and packing means mounted in said counterbore to form a seal around said cylindrical arm means and a packing gland connected to said body means and adapted to compress said packing means.

6. A dilution zone detector in accordance with claim 5 wherein said one end portion of said cylindrical arm means is bent at right angles with respect to said cylindrical arm means and said another end portion carrying said counterweight is bent at right angles with respect to said cylindrical arm means, the axis of said one end portion of said cylindrical arm means and the axis of said another end portion of said cylindrical arm means carrying said counterweight are at right angles with respect to each other.

References Cited by the Examiner UNITED STATES PATENTS 529,191 11/1894 Recknagel 73-228 1,249,484 12/1917 Pogue 73-228 2,017,225 10/1935 Witham 73-32 X 2,033,306 3/1936 Schofield 73-228 RICHARD C. QUEISSER, Primary Examiner. DAVID SCHONBERG, Examiner. 

1. IN COMBINATION: A CONTINUOUS STEADY FLOW REACTION TOWER HAVING A SOURCE OF DILUTION FLUID CONNECTED THERETO BY A HEADER MEANS COMMUNICATING WITH OPENINGS THROUGH SAID TOWER AND A DILUTION ZONE DETECTOR, SAID DILUTION ZONE DETECTOR COMPRISING: CYLINDRICAL MEANS EXTENDING THROUGH THE WALL OF SAID REACTION TOWER, THE INNER PORTION OF SAID CYLINDRICAL ARM MEANS BEING EXPOSED TO THE FORCE CREATED BY THE FLOW OF MATERIALS THROUGH SAID REACTION TOWER, THE OUTER PORTION OF SAID CYLINDRICAL ARM MEANS CARRYING A COUNTERWEIGHT, AND MEANS MOUNTING SAID CYLINDRICAL ARM MEANS IN THE WALL OF SAID REACTION TOWER SO THAT THE INNER PORTION OF SAID CYLINDRICAL ARM 